depends on the muffler shop you go to, and the exhaust tip you buy.
definately. parts-cost would be cheaper..but the labor cost is what you need to worry about. better shops cost more, and that could bump the price over than that of the kazuma.
you would most likely save money though (after all, you need to pay to have kazuma installed anyway)...just make sure you get a good job. mandrel bent piping is better..but many shops don't offer that. (mandrel bent = smoother bends = less restriction = less power loss).